The long-term goal of the proposed research is to develop a comprehensive model to explain the role of visual information in speech perception. Speechreading, a form of human information processing, requires an observer to obtain linguistic information from the movements of a talker's face. Virtually all people, and especially people with hearing loss, rely on visual information in difficult listening situations. The major objectives of this research are: 1) to study visual attention to specific regions of face motion during visual speech perception for individuals who differ in speechreading proficiency; and 2) to determine if attention to specific regions of face motion changes when speechreading improves. Project 1: performance on perceptual tasks in visual speech processing will specify parameters of face motion for visual speech stimuli and study how speechreaders attend to, select and use face motion for visual speech perception. Image processing techniques, such as optic flow analysis, will be used to quantify face motion, and test hypotheses about visual phonetic cues for speech perception. Eye-monitoring techniques will be used to precisely determine facial regions attended to by the speechreader. Comparisons will be made among adults who differ in speechreading proficiency. Subjects include those with normal hearing and hearing loss that may have a congenital-, early-, or adult-onset. Project 2: Chances in perceptual capabilities for improved speechreading accuracy will determine 1) if stimulus, feedback, and task variability during practice improve retention and transfer, and 2) if subjects who improve change patterns of attention and selection for facial regions containing visual phonetic cues. Experimental and control subjects with similar hearing and rehabilitation histories will be compared. Scientific knowledge about visual speech perception will contribute to the development of sensory aids, automatic speech recognition systems, and research-based intervention protocols to augment speech perception.